From its earliest beginnings thousands of years ago, the course of man’s progress has been measured by his empires. Large, dynamic flows of power, people, and culture that merge, thrive, then break apart - the pieces only to merge again in a new configuration, the process to be repeated. Through pictures and words, "Empires: Their Rise and Fall" brings the reader face to face with many of the world’s greatest empires. Full-color photographs are combined with an absorbing narrative in a lively historical account of each empire and an examination of the period’s most enduring cultural achievements. This volume in the series focuses on The USA, and The USSR, both of which are the offspring of revolutions, with the commonality that, for both, the ideals of their revolutions have justified territorial expansion. Unlike the old European colonial empires with possessions scattered around the globe, today’s two superpowers are geographically compact and measure their world-wide influence in terms of allies. Only in their increasingly restive borderlands have the superpowers sought to exert traditional dominion over neighboring states. As history unfolded, a clash of interests between the USA and the USSR was perhaps inevitable, and has evidenced itself over the years, as a myriad of complexities in the Soviet-American relations grows and transforms. The threat of nuclear warfare, however, menacing human survival since 1945, has helped prevent a direct military conflict between the superpowers, which tirelessly raced against each other for influence among the new nations emerging from colonialism in Africa and elsewhere. Whether the very concept of two superpowers astride the world will endure - and to what extent their original ideological precepts will continue to define Soviet and American "missions" - the future will no doubt tell.